the body cranked into a posture that broadcasts sincerity

The A.D.A. leans forward into "the odd defecatory posture men used to try to communicate earnestness" — sincerity performed as a body-position, the self straining its posture to transmit a feeling that won't cross on its own. It is the smile composed and aimed all over again: an interior state that has to be staged physically to have any chance of reading, earnestness turned into a pose precisely because earnestness can't be trusted to broadcast itself.